1. Field of the Invention
The present invention relates to a disk recording and/or reproducing apparatus for recording and/or reproducing informational signals on a disk such as magneto-optical disk and in particular to a disk recording and/or reproducing apparatus including a moving mechanism for moving toward and away from said disk a magnetic head for recording and/or reproducing informational signals on the disk by cooperation with an optical pickup apparatus.
2. Description of the Related Art
The magneto-optical disk having a perpendicularly magnetizable signal recording layer has been proposed as an informational signal recordable disk. In order to record the informational signals on the magneto-optical disk, an area of the signal recording layer is heated to a temperature not lower than so-called Curie temperature by an optical pickup device for converging and impinging a laser beam upon this area and simultaneously an external magnetic field is applied upon this area from an external magnetic field generator. Since the signal recording layer which has been heated to a temperature not lower than Curie temperature has little coercive force, the direction of magnetization is reversed to follow the external magnetic field. Recording of digitialized informational signals can be achieved by reversing the direction of the magnetization of the signal recording layer in such a manner in the magneto-optical disk.
The disk recording and/or reproducing apparatus which performs recording the informational signals to the magneto-optical disk comprises a disk rotating drive mechanism for holding and rotating the magneto-optical disk, the optical pickup apparatus for irradiating the signal recording layer of the magneto-optical disk with the laser beam, and the magnetic head apparatus for applying the external magnetic field to the signal recording layer.
In other words, the disk recording and/or reproducing apparatus rotates the magneto-optical disk, irradiates the signal recording layer of the disk with the optical beam by means of the optical pickup apparatus and applies the external magnetic field to the signal recording layer by means of the magnetic head apparatus so that the informational signals are recorded. The magnetic head is brought into substantial slide contact with the disk for applying the magnetic field upon the signal recording layer. The above mentioned disk recording and/or reproducing apparatus is formed in such a manner that the magnetic head apparatus contacts with the magneto-optical disk on reading of the informational signals recorded on the magneto-optical disk and on stopping of the magneto-optical disk as well as recording of the informational signals on the signal recording layer of the magneto-optical disk.
Accordingly, the durability of the magnetic head apparatus and the magneto-optical disk is diminished since wear of the magnetic head apparatus and the magneto-optical disk occurs due to slide contact therebetween even when the informational signals are not recorded. A load imposed upon the disk rotating drive mechanism is increased due to a fact that the magnetic head apparatus is normally in contact with the magneto-optical disk. Problems such as deterioration of the durability of the disk rotating drive mechanism and an increase in electric power consumption occur.
An approach can be devised that only on recording of the informational signals, the magnetic head is in contact with the magneto-optical disk by moving the magnetic head apparatus by using, for example, a plunger, etc. in response to starting operation of recording of the informational signals. However, if the disk recording and/or reproducing apparatus is formed so that the magnetic head apparatus is merely moved in response to starting operation of recording of the informational signals, the magnetic head apparatus and the magneto-optical disk may be damaged due to collision of the magnetic head apparatus on the magneto-optical disk on this moving operation.